Determining the Minimal Clinically Important Difference (MCID) and Responsiveness of the Chinese Version of Zurich Chronic Middle Ear Inventory (ZCMEI-21-Chn): A Prospective Multicenter Study.

OBJECTIVES: This study aimed to establish the minimal clinically important difference (MCID) and assess the responsiveness of the Chinese version of Zurich Chronic Middle Ear Inventory (ZCMEI-21-Chn).

STUDY DESIGN: Prospective multicenter study.

SETTING: Four Chinese tertiary referral centers admitting patients nationwide.

PATIENTS: 230 adult patients with chronic otitis media (COM) undergoing tympanoplasty.

INTERVENTION: Patients were required to complete the ZCMEI-21-Chn to measure health-related quality of life both preoperatively and postoperatively. An anchor-based method was used to determine the MCID of the derivative cohort by including the Global Rating of Change Questionnaire as an anchor. The generalizability and consistency with functional outcomes of the MCID estimates were externally examined in a validation cohort using a receiver operating characteristic curve analysis.

RESULTS: A total of 161 and 69 patients were included in the derivative and validation cohort. The mean preoperative and postoperative ZCMEI-21-Chn total scores were 28.4 (standard deviation [SD] 14.5) and 17.5 (SD 12.6). The mean change in ZCMEI-21-Chn score was 10.9 (SD 14.3, p < 0.001). The MCIDs of the ZCMEI-21-Chn for improvement and deterioration were estimated at 13 (SD 13.0) and -7 (SD 12.9), accordingly. For patients who have reported an improved health-related quality of life, a cutoff value of 15.6 dB HL for elevation of the air-conducted hearing threshold was noticed. However, change of clinical importance judged according to MCID and Japan Otological Society criteria disagreed with each other, notably with a Cohen's kappa (κ) of 0.14 (p = 0.21) in the validation cohort.

CONCLUSION: This study is the first to establish the MCID of a COM-specific questionnaire in Chinese. For the COM population undergoing surgical intervention, MCID values of 13 for improvement and -7 for deterioration are recommended. The results were externally validated to be generalizable to nationwide usage, yet distinguishable from the audiological criteria. The availability of the MCID greatly adds to the clinical utility of the ZCMEI-21-Chn by enabling a clinically meaningful interpretation of its score changes.